U.S. patent number 8,230,906 [Application Number 12/850,104] was granted by the patent office on 2012-07-31 for dual-chamber fluid pump for a multi-fluid electronics cooling system and method.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to Levi A. Campbell, Richard C. Chu, Michael J. Ellsworth, Jr., Madhusudan K. Iyengar, Roger R. Schmidt, Robert E. Simons.
United States Patent |
8,230,906 |
Campbell , et al. |
July 31, 2012 |
Dual-chamber fluid pump for a multi-fluid electronics cooling
system and method
Abstract
A dual-chamber fluid pump is provided for a multi-fluid
electronics cooling system and method. The pump has a first fluid
path for pumping a first fluid coolant and a second fluid path for
pumping a second fluid coolant, with the first fluid path including
a first pumping chamber and the second fluid path including a
second pumping chamber. The first and second pumping chambers are
separated by at least one diaphragm, and an actuator is coupled to
the diaphragm for transitioning the diaphragm between a first
position and a second position. Transitioning of the diaphragm to
the first position pumps first fluid coolant from the first pumping
chamber while concurrently drawing second fluid coolant into the
second pumping chamber, and transitioning of the diaphragm to the
second position pumps second fluid coolant from the second pumping
chamber while concurrently drawing first fluid coolant into the
first pumping chamber.
Inventors: |
Campbell; Levi A.
(Poughkeepsie, NY), Chu; Richard C. (Hopewell Junction,
NY), Ellsworth, Jr.; Michael J. (Lagrangeville, NY),
Iyengar; Madhusudan K. (Woodstock, NY), Schmidt; Roger
R. (Poughkeepsie, NY), Simons; Robert E. (Poughkeepsie,
NY) |
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
38872519 |
Appl.
No.: |
12/850,104 |
Filed: |
August 4, 2010 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100296248 A1 |
Nov 25, 2010 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11426431 |
Jun 26, 2006 |
7841385 |
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Current U.S.
Class: |
165/80.4;
165/121; 165/104.33; 417/413.1 |
Current CPC
Class: |
H05K
7/20218 (20130101) |
Current International
Class: |
F28D
15/00 (20060101); H05K 7/20 (20060101) |
Field of
Search: |
;165/80.4,104.33,46,121
;417/112,123,413.1,413.2 ;361/699 ;257/714 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Office Action for U.S. Appl. No. 11/426,423 (U.S. Patent
Publication No. 2007/0295480 A1), dated Nov. 27, 2009. cited by
other .
Office Action for U.S. Appl. No. 11/426,431 (U.S. Patent
Publication No. 2007/0295481 A1), dated Jan. 5, 2010. cited by
other.
|
Primary Examiner: Duong; Tho V
Attorney, Agent or Firm: Jung, Esq.; Dennis Radigan, Esq.;
Kevin P. Heslin Rothenberg Farley & Mesiti P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of co-pending U.S.
patent application Ser. No. 11/426,431, filed Jun. 26, 2006,
entitled "Dual-Chamber Fluid Pump for a Multi-Fluid Electronics
Cooling System and Method", by Campbell et al., which published on
Dec. 27, 2007 as U.S. Patent Publication No. 2007/0295481 A1, the
entirety of which is hereby incorporated herein by reference. This
application also contains subject matter which is related to the
subject matter of the following co-pending application, which is
assigned to the same assignee as this application and which is also
hereby incorporated herein by reference in its entirety:
"Multi-Fluid Cooling System, Cooled Electronic module, and Methods
of Fabrication Thereof", Campbell et al., U.S. Ser. No. 11/426,423,
filed Jun. 26, 2006, and published on Dec. 27, 2007 as U.S. Patent
Publication No. 2007/0295480 A1.
Claims
What is claimed is:
1. An apparatus comprising: an electronics cooling system; a pump
for the electronics cooling system, the pump comprising: a first
fluid path for pumping a first fluid coolant of the electronics
cooling system and a second fluid path for pumping a second fluid
coolant of the electronics cooling system, the first fluid path
comprising a first pumping chamber and the second fluid path
comprising a second pumping chamber, the first fluid coolant and
the second fluid coolant being different fluid coolants of the
electronics cooling system, and respectively cool a first
electronic device and a second electronic device; a first diaphragm
and a second diaphragm separating the first pumping chamber and the
second pumping chamber; and an actuator disposed between the first
diaphragm and the second diaphragm for transitioning the first
diaphragm and the second diaphragm between a first position and a
second position, wherein transitioning of the first diaphragm and
the second diaphragm together to the first position pumps first
fluid coolant from the first pumping chamber while concurrently
drawing second fluid coolant into the second pumping chamber, and
transitioning of the first diaphragm and the second diaphragm
together to the second position pumps second fluid coolant from the
second pumping chamber while concurrently drawing first fluid
coolant into the first pumping chamber.
2. The pump of claim 1, wherein the first diaphragm comprises a
wall of the first pumping chamber and the second diaphragm
comprises a wall of the second pumping chamber.
3. The pump of claim 1, wherein the first fluid path is separate
from the second fluid path.
4. The pump of claim 1, wherein the first fluid coolant of the
electronics cooling system is a different fluid coolant than the
second fluid coolant of the electronics cooling system.
5. The pump of claim 4, wherein the first fluid coolant is a
dielectric fluid and the second fluid coolant is an aqueous fluid,
and wherein the actuator is a piezoelectric actuator.
6. The pump of claim 1, wherein the first fluid path further
comprises a first fluid inlet and a first fluid outlet in fluid
communication with the first pumping chamber, and the second fluid
path comprises a second fluid inlet and a second fluid outlet in
fluid communication with the second pumping chamber, wherein the
first fluid inlet, the first fluid outlet, the second fluid inlet
and the second fluid outlet each have associated therewith a
respective check valve to ensure that first fluid coolant flow
through the first fluid path is unidirectional from the first fluid
inlet out through the first fluid outlet and second fluid coolant
flow through the second fluid path is unidirectional from the
second fluid inlet out through the second fluid outlet.
7. The pump of claim 1, wherein the actuator comprises a
piezoelectric actuator disposed between the first diaphragm and the
second diaphragm, the piezoelectric actuator comprising a
piezoelectric material coupled to both the first diaphragm and the
second diaphragm and electrical wiring connected to the
piezoelectric material to facilitate electrical driving of the
piezoelectric material and thereby transitioning the first and
second diaphragms together between the first and second positions,
and wherein the electrical wiring is isolated from the first
pumping chamber and the second pumping chamber by the first
diaphragm and the second diaphragm.
8. A cooled electronic system comprising: a first fluid-cooled
electronic module and a second fluid-cooled electronic module; at
least one heat exchanger for cooling fluid effluent from the first
fluid-cooled electronic module and the second fluid-cooled
electronic module, the fluid effluent comprising a first fluid
coolant and a second fluid coolant, the at least one heat exchanger
comprising a first reservoir for receiving first fluid coolant
output from the first fluid-cooled electronic module and a second
reservoir for receiving second fluid coolant output from the second
fluid-cooled electronic module; a pump for moving the first fluid
coolant to the first fluid-cooled electronic module from the first
reservoir and the second fluid coolant to the second fluid-cooled
electronic module from the second reservoir, the pump comprising: a
first fluid path for pumping the first fluid coolant and a second
fluid path for pumping the second fluid coolant, the first fluid
path comprising a first pumping chamber and the second fluid path
comprising a second pumping chamber; a first diaphragm and a second
diaphragm separating the first pumping chamber and the second
pumping chamber; and an actuator disposed between the first
diaphragm and the second diaphragm for transitioning the first
diaphragm and the second diaphragm between a first position and a
second position, wherein when operational, transitioning the first
diaphragm and the second diaphragm together to the first position
pumps first fluid coolant from the first pumping chamber while
concurrently drawing second fluid coolant into the second pumping
chamber, and transitioning the first diaphragm and the second
diaphragm together to the second position pumps second fluid
coolant from the second pumping chamber while concurrently drawing
first fluid coolant into the first pumping chamber; and a first
coolant loop coupling the first fluid path of the pump to a fluid
inlet of the first fluid-cooled electronic module and a second
coolant loop coupling the second fluid path of the pump to a fluid
inlet of the second fluid-cooled electronic module.
9. The cooled electronics system of claim 8, wherein the first
diaphragm comprises a wall of the first pumping chamber and the
second diaphragm comprises a wall of the second pumping
chamber.
10. The cooled electronics, system of claim 8, wherein the first
fluid coolant is a different fluid coolant than the second fluid
coolant.
11. The cooled electronics system of claim 8, wherein the first
fluid coolant is a dielectric fluid and the second fluid coolant is
an aqueous fluid.
12. The cooled electronics system of claim 8, wherein the actuator
is a piezoelectric actuator, the piezoelectric actuator comprising
a piezoelectric material coupled to the first diaphragm and the
second diaphragm.
13. A method of cooling a first fluid-cooled electronic module and
a second fluid-cooled electronic module, the method comprising:
providing a pump for pumping a first fluid coolant and a second
fluid coolant to the first fluid-cooled electronic module and the
second fluid-cooled electronic module, respectively, the pump
comprising: a first fluid path for pumping the first fluid coolant
and a second fluid path for pumping the second fluid coolant, the
first fluid path comprising a first pumping chamber and the second
fluid path comprising a second pumping chamber; a first diaphragm
and a second diaphragm separating the first pumping chamber and the
second pumping chamber; and an actuator disposed between the first
diaphragm and the second diaphragm for transitioning the first
diaphragm and the second diaphragm between a first position and a
second position, wherein transitioning the first diaphragm and the
second diaphragm to the first position pumps first fluid coolant
from the first pumping chamber while concurrently drawing second
fluid coolant into the second pumping chamber, and transitioning
the first diaphragm and the second diaphragm to the second position
pumps second fluid coolant from the second pumping chamber while
concurrently drawing first fluid coolant into the first pumping
chamber; employing the actuator to vibrate the first diaphragm and
the second diaphragm together between the first position and the
second position, wherein the vibrating continuously alternately:
pumps first fluid coolant from the first pumping chamber while
concurrently drawing second fluid coolant into the second pumping
chamber; pumps second fluid coolant from the second pumping chamber
while concurrently drawing first fluid coolant into the first
pumping chamber; and providing a first coolant loop coupling the
first fluid path of the pump to the first fluid-cooled electronic
module and a second coolant loop coupling the second fluid path of
the pump to a fluid inlet of the second fluid-cooled electronic
module, and wherein the method further comprises employing the pump
to concurrently provide first fluid coolant to the first
fluid-cooled electronic module and second fluid coolant to the
second fluid-cooled electronic module, and wherein the method
further comprises providing at least one heat exchanger for cooling
first fluid coolant output from the first fluid-cooled electronic
module and second fluid coolant output from the second fluid-cooled
electronic module, the at least one heat exchanger comprising a
first reservoir for receiving the first fluid coolant output from
the first fluid-cooled electronic module and a second reservoir for
receiving the second fluid coolant output from the second
fluid-cooled electronic module.
14. The method of claim 13, wherein the first diaphragm comprises a
wall of the first pumping chamber and the second diaphragm
comprises a wall of the second pumping chamber.
15. The method of claim 13, wherein the first fluid path is
separate from the second fluid path, and the first fluid coolant
and the second fluid coolant respectively cool a first electronic
device and a second electronic device.
16. The method of claim 15, wherein the first fluid coolant is a
different fluid coolant than the second fluid coolant.
17. The method of claim 16, wherein the first fluid coolant is a
dielectric fluid and the second fluid coolant is an aqueous fluid,
and wherein the actuator is a piezoelectric actuator.
Description
TECHNICAL FIELD
The present invention relates generally to heat transfer
mechanisms, and more particularly, to cooling systems, cooled
electronic modules and methods of fabrication thereof for removing
heat generated by one or more electronic devices. Still more
particularly, the present invention relates to multi-fluid cooling
systems and methods of cooling one or more electronic devices, and
in particular, to a multi-chamber fluid pump for pumping different
fluids through a multi-fluid cooling system.
BACKGROUND OF THE INVENTION
As is known, operating electronic devices produce heat. This heat
must be removed from the devices in order to maintain device
junction temperatures within desirable limits, with failure to
remove the heat thus produced resulting in increased device
temperatures, potentially leading to thermal runaway conditions.
Several trends in the electronics industry have combined to
increase the importance of thermal management, including
technologies where thermal management has traditionally been less
of a concern, such as CMOS. In particular, the need for faster and
more densely packed circuits has had a direct impact on the
importance of thermal management. First, power dissipation, and
therefore heat production, increases as device operating
frequencies increase. Second, increased operating frequencies may
be possible at lower device junction temperatures. Further, as more
and more devices are packed onto a single chip, power density
(Watts/cm.sup.2) increases, resulting in the need to remove more
power from a given size chip or module. These trends have combined
to create applications where it is no longer desirable to remove
heat from modern devices solely by traditional air cooling methods,
such as by using air cooled heat sinks with heat pipes or vapor
chambers. Air cooling techniques are inherently limited in their
ability to extract heat from an electronic device with high power
density.
SUMMARY OF THE INVENTION
The need to cool current and future high heat load, high heat flux
electronic devices requires development of aggressive thermal
management techniques, such as liquid impingement approaches to
cool the electronic devices. The concepts disclosed herein address
this need for enhanced fluid-based cooling systems and methods of
cooling. More particularly, enhanced pump designs are presented for
use in such fluid-based cooling systems and methods.
Briefly summarized, the present invention comprises in one aspect a
pump for an electronics cooling system. The pump includes a first
fluid path for pumping a first fluid coolant and a second fluid
path for pumping a second fluid coolant, with the first fluid path
comprising a first pumping chamber and the second fluid path
comprising a second pumping chamber. The pump further includes at
least one diaphragm separating the first pumping chamber and the
second pumping chamber, and an actuator coupled to the at least one
diaphragm for transitioning the at least one diaphragm between a
first position and a second position. When the pump is operational,
transitioning of the at least one diaphragm to the first position
pumps first fluid coolant from the first pumping chamber while
concurrently drawing second fluid coolant into the second pumping
chamber, and transitioning of the at least one diaphragm to the
second position pumps second fluid coolant from the second pumping
chamber while concurrently drawing first fluid coolant into the
first pumping chamber.
In another aspect, the present invention comprises a cooled
electronics system, which includes at least one fluid-cooled
electronic module and at least one heat exchanger for cooling fluid
effluent from the at least one fluid-cooled electronic module. The
fluid effluent comprises a first fluid coolant and a second fluid
coolant. Further, a pump is provided for pumping the first fluid
coolant and the second fluid coolant to the at least one
fluid-cooled electronic module from the at least one heat
exchanger. The pump includes a first fluid path for pumping the
first fluid coolant and a second fluid path for pumping the second
fluid coolant, with the first fluid path comprising a first pumping
chamber and the second fluid path comprising a second pumping
chamber. The pump further includes at least one diaphragm
separating the first pumping chamber and the second pumping
chamber, and an actuator coupled to the at least one diaphragm for
transitioning the at least one diaphragm between a first position
and a second position. When operational, transitioning of the at
least one diaphragm to the first position pumps first fluid coolant
from the first pumping chamber while concurrently drawing second
fluid coolant into the second pumping chamber, and transitioning of
the at least one diaphragm to the second position pumps second
fluid coolant from the second pumping chamber while concurrently
drawing first fluid coolant into the first pumping chamber.
In a further aspect, the present invention comprises a method of
cooling at least one fluid-cooled electronic module. The method
includes providing a pump for pumping a first fluid coolant and a
second fluid coolant to the at least one fluid-cooled electronic
module. The pump includes: a first fluid path for pumping the first
fluid coolant and a second fluid path for pumping the second fluid
coolant, the first fluid path comprising a first pumping chamber
and the second fluid path comprising a second pumping chamber; at
least one diaphragm separating the first pumping chamber and the
second pumping chamber; and an actuator coupled to the at least one
diaphragm for transitioning the at least one diaphragm between a
first position and a second position, wherein transitioning of the
at least one diaphragm to the first position pumps first fluid
coolant from the first pumping chamber while concurrently drawing
second fluid coolant into the second pumping chamber, and
transitioning of the at least one diaphragm to the second position
pumps second fluid coolant from the second pumping chamber while
concurrently drawing first fluid coolant into the first pumping
chamber. The method further includes employing the actuator to
vibrate the at least one diaphragm between the first position and
the second position, wherein the vibrating continuously
alternately: pumps first fluid coolant from the first pumping
chamber while concurrently drawing second fluid coolant into the
second pumping chamber; and pumps second fluid coolant from the
second pumping chamber while concurrently drawing first fluid
coolant into the first pumping chamber.
Further, additional features and advantages are realized through
the techniques of the present invention. Other embodiments and
aspects of the invention are described in detail herein and are
considered a part of the claimed invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
objects, features, and advantages of the invention are apparent
from the following detailed description taken in conjunction with
the accompanying drawings in which:
FIG. 1 is an isometric view of one embodiment of a conventional
piezoelectric fluid pump;
FIG. 2 is a graph of the transient flow characteristics for the
conventional piezoelectric fluid pump of FIG. 1;
FIG. 3 is a cross-sectional elevational view of one embodiment of a
dual-chamber fluid pump, in accordance with an aspect of the
present invention;
FIG. 4 is a cross-sectional elevational view of the dual-chamber
fluid pump of FIG. 3, showing transitioning of the diaphragm to a
first position resulting in concurrent pumping of a first fluid
coolant from a first (e.g., upper) pumping chamber and drawing of a
second fluid coolant into a second (e.g., lower) pumping chamber,
in accordance with an aspect of the present invention;
FIG. 5 is a cross-sectional elevational view of the dual-chamber
fluid pump of FIGS. 3 & 4, showing transitioning of the
diaphragm to a second position resulting in concurrent pumping of
the second fluid coolant from the second pumping chamber and
drawing of the first fluid coolant into the first pumping chamber,
in accordance with an aspect of the present invention;
FIG. 6A is a graph of transient flow characteristics of the first
fluid coolant flow rate versus time through the first fluid flow
path (comprising the first pumping chamber), in accordance with an
aspect of the present invention;
FIG. 6B is a graph of transient flow characteristics of the second
fluid coolant flow rate versus time through the second fluid flow
path (comprising the second pumping chamber), in accordance with an
aspect of the present invention;
FIG. 7 depicts one embodiment of a cooled electronics system, in
accordance with an aspect of the present invention;
FIG. 8 depicts an alternate embodiment of a cooled electronics
system, in accordance with an aspect of the present invention;
FIG. 9 is a cross-sectional elevational view of an alternate
embodiment of a dual-chamber fluid pump, in accordance with an
aspect of the present invention;
FIG. 10 is a graph of transient flow characteristics depicting
continuous outflow of fluid from and continuous inflow of fluid to
the dual-chamber fluid pump of FIG. 9, in accordance with an aspect
of the present invention;
FIG. 11 is a cross-sectional elevational view of another embodiment
of a dual-chamber fluid pump, showing the diaphragm in a first
position to pump a first fluid coolant from the first pumping
chamber and concurrently draw a second fluid coolant into the
second pumping chamber, in accordance with an aspect of the present
invention; and
FIG. 12 depicts the dual-chamber fluid pump of FIG. 11, showing the
diaphragm in a second position to pump second fluid coolant from
the second pumping chamber and concurrently draw first fluid
coolant into the first pumping chamber, in accordance with an
aspect of the present invention.
DETAILED DESCRIPTION
As used herein "electronic device" comprises any heat generating
electronic component of a computer system or other electronic
system requiring cooling. In one example, the electronic device is
or includes one or more integrated circuit chips, and/or electronic
components. The term "fluid-cooled electronic module" includes any
electronic module with liquid cooling and at least one electronic
device, with single-chip modules and multi-chip modules being
examples of a cooled electronic module as described herein. The
"surface to be cooled" refers to a surface of one or more
electronic devices, or to an exposed surface of a thermal cap,
thermal spreader, passivation layer, or other surface in contact
with the one or more electronic devices, and through which heat
generated by the electronic device(s) is to be extracted.
Generally stated, provided herein is an enhanced dual-chamber fluid
pump and cooled electronics system and method employing the
enhanced pump. In one embodiment, the pump includes a first fluid
path for pumping a first fluid coolant and a second fluid path for
pumping a second fluid coolant, with the first fluid path
comprising a first pumping chamber and the second fluid path
comprising a second pumping chamber. The pumping chambers are
separated by at least one diaphragm and an actuator is coupled to
the diaphragm(s) for transitioning the diaphragm(s) between a first
position and a second position. Transitioning of the diaphragm(s)
to the first position pumps first fluid coolant from the first
pumping chamber while concurrently drawing second fluid coolant
into the second pumping chamber, and transitioning of the
diaphragm(s) to the second position pumps second fluid coolant from
the second pumping chamber while concurrently drawing first fluid
coolant into the first pumping chamber. The dual-chamber fluid pump
is particularly advantageous when employed in a cooled electronics
system comprising a multi-fluid-cooled electronic module such as
described in the above-incorporated, co-filed U.S. Patent
Application entitled, "Multi-Fluid Cooling System, Cooled
Electronic module, and Methods of Fabrication Thereof". However,
those skilled in the art will note that the dual-chamber fluid pump
described herein has many applications in the art, including an
ability to pump two different fluid coolants to two different
fluid-cooled electronic modules.
Two cooling solutions for addressing high heat flux in electronic
devices are indirect liquid cooling via a cold plate and direct
liquid cooling employing a manifold structure. In either approach,
the cooling system requires a pump (or coolant flow drive
apparatus) to move fluid coolant through the system. Designing
pumps for such high performance liquid cooling systems requires
substantial attention to attributes such as the ability to generate
the requisite pressure head and coolant flow rate, and the size and
the reliability of the pumps. Piezoelectric pumps are a viable
option for applications where moderate flow rate and pressure head,
small form factor, and high reliability are desirable
characteristics.
FIG. 1 depicts an example of a conventional piezoelectric pump,
generally denoted 100, implementations of which are commercially
available through Deak Technologies, Inc., of Brooklyn, N.Y., USA.
Piezoelectric pump 100 includes a fluid inlet port 110 and a fluid
exit port 120. A lower chamber 140 within the pump is filled with
fluid and in fluid communication with fluid inlet port 110 and
fluid exit port 120. A diaphragm 135 divides lower chamber 140 from
an upper chamber 130 filled with air, with appropriate vents (not
shown) being provided to upper chamber 130.
Upper chamber 130 of pump 100 houses a piezoelectric actuator (not
shown) attached to diaphragm 135, which again separates the
liquid-filled lower chamber 140 from the air-filled upper chamber
130. The actuator, along with the diaphragm, physically deflect
when the actuator is energized by an oscillating voltage, with the
maximum deflection being at the center. For half an operational
cycle, the actuator and diaphragm deflect to a maximum position in
one direction normal to the plane of the actuator, and in the
following half of the cycle, the actuator and diaphragm deflect to
a maximum position in the opposite direction. One-way valves in
fluid inlet port 110 and fluid exit port 120 ensure that fluid only
flows through the inlet port and out from the exit port. The
resulting flow characteristic of the pump is plotted in FIG. 2. As
shown, pump 100 provides fluid output (i.e., positive outflow) only
one-half of the time. The other half of the operational cycle is
devoted to drawing fluid into the liquid-filled lower chamber.
The enhanced pump presented herein address two limitations to the
single-fluid chamber pump design of FIG. 1, namely: the ability to
pump only a single type of fluid; and the ability to pump fluid for
only one-half the total time, with only one-half of the total
actuator deflection or transition being utilized to pump fluid
out.
FIG. 3 depicts one embodiment of a dual-chamber fluid pump 300, in
accordance with an aspect of the present invention. Pump 300
includes an upper casing 310 and a lower casing 320 configured to
sealably engage and define a first (e.g., upper) pumping chamber
340 and a second (e.g., lower) pumping chamber 350 separated by a
diaphragm 330. More particularly, upper casing 310 defines an upper
seat 312 along the periphery thereof, while lower casing 320
includes an inwardly projecting lower seat 322. A circular upper
gasket 314 and a circular lower gasket 324 are disposed on either
side of the diaphragm, and are sized to accommodate and secure a
peripheral edge of diaphragm 330 therebetween when positioned
between the diaphragm and a respective one of the upper and lower
seats. Upper gasket 314 and lower gasket 324 further function to
fluidically isolate fluid flow through the first pumping chamber
340 from fluid flow through the second pumping chamber 350.
A first fluid path is defined across the upper portion of pump 300
through a first fluid inlet 342, first pumping chamber 340, and a
first fluid outlet 344, which are all in fluid communication as
shown. First fluid inlet 342 and first fluid outlet 344 each
include a check valve 343, 345, respectively, which together ensure
unidirectional fluid flow through the first fluid path from the
first fluid inlet, through the first pumping chamber and out
through the first fluid outlet.
Similarly, a second fluid path is defined across the lower portion
of pump 300 through a second fluid inlet 352, second pumping
chamber 350, and a second fluid outlet 354, which are also all in
fluid communication as shown. Again, second fluid inlet 352
includes a check valve 353, and second fluid outlet 354 includes a
check valve 355, which cooperate to ensure unidirectional fluid
flow through the second fluid path from the second fluid inlet,
through the second pumping chamber and out through the second fluid
outlet.
In this embodiment, the actuator is (by way of example) a
piezoelectric actuator, with a first terminal post 361 and a second
terminal post 362 providing input voltage to piezoelectric material
360 coupled to diaphragm 330. As is understood in the art,
piezoelectric material 360 expands or contracts when voltage is
applied across it. This phenomenon is employed to transition
diaphragm 330 between a first and second position, as explained
further below with reference to FIGS. 4 & 5. Further, first
pumping chamber 340 is filled, in one example, with a dielectric
coolant, and second pumping chamber 350 is filled with an aqueous
coolant. Thus, the electrical wiring connections to the actuator
reside in the first pumping chamber, which provides for an
electrically inert environment (i.e., the dielectric fluid).
Alternatively, if second pumping chamber 350 includes a dielectric
fluid, then the piezoelectric actuator could be designed to reside
in second pumping chamber 350.
Operationally, in one example, actuator 360 is configured to
transition diaphragm 330 in a first half of the operational cycle
to a first (convex) position shown in FIG. 4 to pump first fluid
coolant from first pumping chamber 340 via first fluid outlet 344
and to draw second fluid coolant into second pumping chamber 350
via second fluid inlet 352. This first half of the operational
cycle is depicted in FIGS. 6A & 6B, wherein in FIG. 6A,
positive outflow of first fluid coolant is shown and in FIG. 6B,
inflow of second fluid coolant into the pump is shown occurring
concurrent therewith. More particularly, by deflecting the
diaphragm towards the first pumping chamber (see FIG. 4), pressure
rises in the first pumping chamber, resulting in the opening of the
one-way valve at first fluid outlet 344 and the pumping out of the
first fluid coolant from the first pumping chamber under pressure.
Concurrent with this, pressure in the second pumping chamber is
reduced due to the increased volume in the chamber, thus resulting
in the opening of the one-way valve at the second fluid inlet 352,
which in turn results in second fluid coolant flow into the second
pumping chamber. During this operation, the one-way valves at the
first fluid inlet 342 and second fluid outlet 354 remain
closed.
FIG. 5 depicts transitioning of diaphragm 330 to a second, concave
position in the remainder of the operational pump cycle. During the
second half of the cycle, diaphragm 330 deflects or returns to a
lower extreme position and the first fluid coolant is drawn into
first pumping chamber 340 through first fluid inlet 342, while the
second fluid coolant is pumped from second pumping chamber 350
through second fluid outlet 354. This is again shown in the coolant
flow rate diagrams of FIGS. 6A & 6B, wherein in the second half
of the operational cycle, FIG. 6A illustrates the first fluid
coolant inflow into the first pumping chamber, while FIG. 6B
illustrates positive second fluid coolant outflow from the second
pumping chamber. This inflow/outflow process then repeats for each
operational cycle of the pump.
By way of specific example, the piezoelectric actuator is a
piezoelectric disk-shaped actuator made of Barium Titanate (ceramic
BaTiO.sub.3) or Lead Zirconate Titanate (ceramic PZT), which are
both manufactured by Ecertec Limited, of Leeds, United Kingdom. PZT
is also fabricated by American Piezo Ceramics, Inc., of
Mackeyville, Pa., USA. An electrical potential of several hundred
volts of alternating voltage (e.g., 100-1,000 VDC) creates a
deflection of 0.025-0.1 mm in a 25 mm diameter disk. This device
will typically be operated at frequencies of several hundred cycles
per second. The disk-shaped actuator is bonded to the larger
disk-shaped diaphragm (e.g., membrane) using an adhesive or bonding
agent. The diaphragm may be made of a polymeric material.
Alternatively, the piezoelectric material need not be ceramic, but
a polymeric material such as a fluoropolymer, e.g., Polyvinyledene
Fluoride (PVDF) made in powder form by SOLVAY Advanced Polymers,
LLC, of Alpharetta, Ga., USA.
Although principally described herein as a piezoelectric actuator
with a piezoelectric material which deforms when subjected to an
electrical potential across the material, other actuation
mechanisms could be employed to transition the diaphragm between a
first position and second position. For example, shape memory
alloys which deform when heated or cooled could be employed, with
the heating performed by joule heating from the passage of an
electric current through the actuator. An example of this material
is Nickel-Titanium alloy such as Nitinol offered by Memry Corp., of
Bethel, Conn., USA. Alternatively, magnetic fields could be
employed to cause dynamic deflection of the membrane using
materials such as magneto-restrictive materials. An example of a
magneto-restrictive material is Terfonal-D (an alloy of Terbium,
Dysprosium, and Iron), fabricated by ETREMA Products, Inc., of
Ames, Iowa, USA.
FIG. 7 depicts one embodiment of a cooled electronics system 700,
in accordance with an aspect of the present invention. In this
embodiment, a dual-chamber fluid pump 300, such as described above
in connection with FIGS. 3-5, is employed to circulate a first
fluid coolant and a second coolant fluid, which by way of example,
are a dielectric coolant, and an aqueous coolant, respectively. The
two different fluids are provided to a multi-fluid-cooled
electronic module 720 such as described above in the incorporated,
co-filed patent application entitled, "Multi-Fluid Cooling System,
Cooled Electronic module, and Methods of Fabrication Thereof".
Briefly summarized, this incorporated application describes
enhanced cooling systems and methods of cooling which allow for
high heat transfer from a surface of an electronic device to be
cooled using a direct multi-fluid impingement approach. The
multi-fluid coolants include a first fluid (i.e., a first liquid)
and a second fluid (i.e., a second liquid), which are immiscible
and have different densities. Additionally, the first fluid has a
significantly lower boiling point temperature than the second
fluid. The multi-fluid-cooled electronic module includes a manifold
structure comprising a first fluid inlet orifice and a second fluid
inlet orifice for concurrently separately injecting the first fluid
and the second fluid in close association with one another onto a
surface to be cooled. When the cooling system is employed to cool
one or more electronic devices and the first fluid boils, evolving
first fluid vapor condenses in situ over the surface to be cooled
by direct contact with the second fluid of higher boiling point
temperature. By way of specific example, the first fluid may
comprise a fluorocarbon, a segregated hydrofluoroether (HFE) or a
refrigerant, and the second fluid, water.
As shown in FIG. 7, cooled electronics system 700 includes, in
addition to multi-fluid-cooled electronic module 720 and
dual-chamber fluid pump 300, a reservoir 730 which functions as a
fluid separator and a heat exchanger. An effluent comprising an
emulsion of the first fluid coolant and the second fluid coolant is
output through an exit port 722 in multi-fluid-cooled electronic
module 720 to reservoir 730 via a multi-fluid return line 723. The
emulsion comprises separate globules of the dielectric fluid and
water, which due to their immiscibility and different specific
gravities, separate into two distinct layers or volumes 732, 734
within reservoir 730, with the dielectric at the bottom of the
reservoir and water at the top. An air space 735 and a pressure
relief valve (not shown) are also provided within reservoir 730 to
ensure maintenance of pressure within the reservoir below a set
limit.
As shown, reservoir 730 also functions as a heat exchanger with at
least one cooling loop 740 passing therethrough between a coolant
inlet 742 and a coolant outlet 744. Cooled dielectric fluid is
drawn from the reservoir via a supply line 733 to first fluid inlet
342 of dual-chamber fluid pump 300, while cooled water is drawn
from the reservoir via supply line 735 to second fluid inlet 352 of
dual-chamber fluid pump 300. Supply lines 733 and 735 couple to
reservoir 730 at levels of the tank always below and always above,
respectively, the dielectric-water interface.
Dual-chamber fluid pump 300 simultaneously circulates dielectric
fluid through the first flow path (comprising first pumping chamber
340) and water through the second flow path (comprising second
pumping chamber 350), as explained above. The two fluids are
respectively provided (via a first coolant loop 710) to a first
fluid inlet 711 of multi-fluid-cooled electronic module 720 and
(via a second coolant loop 712) to a second fluid inlet 713 of
multi-fluid-cooled electronic module 720. In operation, heat from
the one or more electronic devices within electronic module 720 is
rejected to the first and second fluid coolants passing
therethrough, which in turn reject the heat at the reservoir to,
for example, chilled water passing through the cooling loop of the
heat exchanger. In one example, this chilled water could be
supplied by a coolant distribution unit or computer room water
conditioning unit.
FIG. 8 depicts an alternate implementation of a cooled electronics
system 800 employing a dual-chamber fluid pump 300, in accordance
with an aspect of the present invention. In this electronics
system, a first fluid-cooled electronic module 820 and a second
fluid-cooled electronic module 830 are both supplied with coolant
from a single dual-chamber fluid pump 300 (such as described above
in connection with FIGS. 3-5), with both coolant loops being
isolated from one another and containing a same type or different
types of coolant.
As shown in FIG. 8, a first fluid coolant is pumped from first
pumping chamber 340 through first fluid outlet 344 (via a first
fluid loop 810) to first fluid-cooled electronic module 820, and a
second fluid coolant is pumped from second pumping chamber 350
through second fluid outlet 355 (via a second cooling loop 812) to
second fluid-cooled electronic module 830. The heated first fluid
coolant from first fluid-cooled electronic module 820 is returned
via return line 822 to a first portion 844 of a reservoir 840, and
the heated second fluid coolant is returned via a return line 832
to a second portion 842 of reservoir 840. Portions 844 and 842 are
assumed to be isolated portions of reservoir 840, which again in
this example, also functions as a heat exchanger with at least one
coolant flow path 850 passing through both portions of the
reservoir. First fluid coolant 845 substantially fills first
reservoir portion 844, except for an air space 846 (with a pressure
relief valve (not shown) to ensure maintenance of pressure within
the reservoir portion 844 below a set limit), while second fluid
843 substantially fills second reservoir portion 842, except for an
air space 841 (and a pressure relief valve (not shown), again to
ensure maintenance of pressure within reservoir portion 842 below a
set limit). Coolant is fed through the heat exchanger cooling loop
850 from a coolant inlet 852 to a coolant outlet 854. By way of
example, the chilled coolant passing through the heat exchanger
could comprise chilled water supplied by a coolant distribution
unit or a computer room water conditioning unit.
A first supply line 853 couples reservoir portion 844 to first
fluid inlet 342 of dual-chamber fluid pump 300, for drawing of the
first fluid coolant to the first fluid path of the pump, and a
second supply line 851 couples reservoir portion 842 to second
fluid inlet 352 of dual-chamber fluid pump 300 for drawing of the
second fluid coolant to the second fluid path of the pump. By way
of example, the first fluid coolant passing through the first
fluid-cooled electronic module 820 is a dielectric, while the
second fluid coolant passing through second fluid-cooled electronic
module 830 is water. Advantageously, this allows use of a
piezoelectric actuator to drive the diaphragm separating the first
pumping chamber 340 from the second pumping chamber 350, with the
electrical lines coupling to the piezoelectric material passing
through the first pumping chamber as illustrated in FIG. 8.
Operation of pump 300 is again analogous to that described above in
connection with FIGS. 3-5.
FIG. 9 depicts an alternate embodiment of a dual-chamber fluid
pump, in accordance with an aspect of the present invention. This
fluid pump 900 includes an upper casing 910 and a lower casing 920,
which together with a first diaphragm 930 and a second diaphragm
940 define a first pumping chamber 950 and a second pumping chamber
960. A first fluid path is defined in the upper portion of
dual-chamber fluid pump 900 through a first fluid inlet 952, first
pumping chamber 950 and a first fluid outlet 954, while a second
fluid path is defined in the lower portion of dual-chamber fluid
pump 900 through second fluid inlet 962, second pumping chamber 960
and a second fluid outlet 964. One-way valves 953 & 955 ensure
unidirectional flow of a first fluid coolant through the first
fluid path, and one-way valves 963, 965 ensure unidirectional flow
of a second fluid coolant through the second fluid path.
Upper casing 910 includes a perimeter surface 912 which functions
as an upper seat, and lower casing 920 includes an inwardly
projecting lower seat 922, between which the first and second
diaphragms 930 & 940 are held along their perimeters. In one
example, the upper and lower diaphragms are disk-shaped and are
held in spaced relation between an epoxy material 980 (sandwiched
between the diaphragms) and an upper circular gasket 914
(sandwiched between the upper seat and the upper diaphragm) and a
lower circular gasket 924 (sandwiched between the lower seat and
the lower diaphragm). Epoxy material 980 functions to seal the
space between the diaphragms holding the piezoelectric material 970
of a piezoelectric actuator. In this example, a first terminal post
971 provides electrical connection to a perimeter of piezoelectric
material 970, while a second terminal post 972 electrically
connects to a middle portion of piezoelectric material 970. By
applying an alternating voltage across the first terminal post and
second terminal post, piezoelectric material 970 transitions
causing first membrane 930 and second membrane 940 to vibrate
together, thereby alternately effecting pumping of first fluid
coolant from first pumping chamber 950 and second fluid coolant
from second pumping chamber 960.
Advantageously, in the FIG. 9 embodiment, the two diaphragms attach
to the same piezoelectric actuator, and the electrical wiring for
the actuator is isolated from both the first pumping chamber and
the second pumping chamber. Thus, the first fluid coolant in the
first pumping chamber and the second fluid coolant in the second
pumping chamber may each be an aqueous coolant. Thus, in one
embodiment, the two chambers can supply the same coolant (for
example, water), to different loops passing through different
fluid-cooled electronic modules, or can be connected together at
their outlets and at their inlets, thus enabling twice the flow
rate than possible with a comparably sized conventional
piezoelectric pump. This flow characteristic is depicted in FIG.
10, where a constant flow rate of fluid is pumped from the
dual-chamber fluid pump and a constant rate of fluid is drawn into
the dual-chamber fluid pump, again when viewed from where the pump
outlets are connected together, and the pump inlets are connected
together.
FIGS. 11 & 12 depict a further alternate embodiment of a
dual-chamber fluid pump 1100, in accordance with an aspect of the
present invention. In this embodiment, the pump again includes an
upper casing 1110 and a lower casing 1120 which, along with
diaphragm 1130, define a first pumping chamber 1140 and a second
pumping chamber 1150. The upper and lower casings are configured to
define seats along the periphery of the diaphragm 1130 which hold
the diaphragm in position employing upper and lower circular
gaskets, as explained above in connection with the embodiments of
FIGS. 3-5. A first fluid path is defined through the upper portion
of the pump from a first fluid inlet 1142, through first pumping
chamber 1140, and out a first fluid outlet 1144, while a second
fluid path is defined from a second fluid inlet 1152, through
second pumping chamber 1150, and out a second fluid outlet 1154. In
this embodiment, the diaphragm transitions between a first
position, shown to be a convex position in FIG. 11, and a second
position, shown to be a planar position in FIG. 12. As shown in
FIG. 11, in the first position, first fluid coolant is pumped from
first pumping chamber 1140 out first fluid outlet 1144, while
concurrently second fluid coolant is drawn into second pumping
chamber 1150 through second fluid inlet 1152. Conversely, as shown
in FIG. 12, in the second diaphragm position, second fluid coolant
is pumped from second pumping chamber 1150 out second fluid outlet
1154, while first fluid coolant is concurrently drawn into first
pumping chamber 1140 through first fluid inlet 1142. The actuation
mechanism is again, in one example, a piezoelectric actuator 1160,
with the first fluid coolant passing through the first fluid path
being a dielectric and the second fluid coolant passing through the
second fluid path being water.
Those skilled in the art will note from the above description that
provided herein is a dual-chamber fluid pump for an electronics
cooling system and method, wherein the two fluid paths are isolated
and, in one embodiment, occupied by two different coolants. Thus, a
single dual-chamber fluid pump can supply two different fluid
coolants for cooling a single electronic module or for cooling at
least two different electronic modules. Depending on the
implementation, the cooled electronics system can include a common
reservoir which also functions as a heat exchanger for the two
different fluid coolants provided to the dual-chamber fluid pump.
By way of specific example, one fluid coolant is a dielectric
fluid, while the other fluid coolant is aqueous. Driving of the
diaphragm separating the pumping chambers can be accomplished
employing a piezoelectric material to vibrate the diaphragm. In
such an implementation, the piezoelectric material and electrical
connections can reside in the pumping chamber containing the
dielectric coolant. As a further variation, two diaphragms may be
employed sandwiching an actuation mechanism, which when stimulated,
causes vibration of the diaphragms to alternately discharge and
draw in fluid coolant to the two different pumping chambers.
Additional advantages of the structures and processes described
herein will be apparent to those of ordinary skill in the art.
Although preferred embodiments have been depicted and described in
detail herein, it will be apparent to those skilled in the relevant
art that various modifications, additions, substitutions and the
like can be made without departing from the spirit of the
invention, and that these are therefore considered to be within the
scope of the invention as defined in the following claims.
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